Piston for an internal combustion engine
A piston for an internal combustion engine has an annular cooling channel provided with oil admission boreholes and oil discharge boreholes, the oil discharge boreholes being oriented in the direction of the bolt hubs for the cooling thereof.
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This application is the National Stage of PCT/DE2006/002254 filed on Dec. 15, 2006, which claims priority under 35 U.S.C. §119 of German Application No. 10 2005 061 059.5 filed on Dec. 21, 2005. The international application under PCT article 21(2) was not published in English.
The invention relates to a piston for an internal combustion engine, in accordance with the preamble of claim 1.
A piston is known from the published application DE 102 14 830 Al, which has a ring-shaped cooling channel disposed in the edge region on the piston crown side, which channel has an oil inlet opening on the side facing away from the piston crown, by way of which opening an oil spray nozzle sprays cooling oil into the cooling channel. The cooling channel is delimited radially on the outside by a molded-on part that carries the ring belt, and radially on the inside by the piston crown shaped to configure the combustion bowl, so that cooling oil flowing in the cooling channel can only cool the ring belt and the radially outer region of the combustion bowl.
A piston is known from the Japanese patent application JP 09 079116, in which the entire underside of the piston crown has cooling oil sprayed onto it, and is thereby cooled.
It is a disadvantage in this connection that neither in the Offenlegungsschrift DE 102 14 830 nor in the Japanese patent application JP 09 079116 are any measures provided that serve for cooling the pin bosses.
Proceeding from this, the invention is based on the task of avoiding the stated disadvantage of the state of the art. This task is accomplished with the characteristics that stand in the characterizing part of the main claim and the secondary claim. Practical embodiments of the invention are the object of the dependent claims.
Some exemplary embodiments of the invention will be described below, using the drawing. This shows:
The piston-crown-side regions 12 of the pin bosses 10 are reinforced radially on the inside, as can be seen particularly well also in
Oil pockets 13 and 14 are formed into the radially inner sides of the piston-crown-side regions 12 of the pin bores 11, the purpose of which pockets consists in storing oil during engine operation, which oil is utilized for improved lubrication of the piston pin (not shown in the figure). This additionally contributes to a reduction in the wear of the piston pin and the pin bore 11.
The oil required for cooling the ring insert 4 is sprayed directly into the cooling channel 5 disposed radially within the ring insert 4, by at least one oil spray nozzle 16, by way of an oil run-in bore 17, in each instance. After passing through the cooling channel 5, the oil exits again from oil run-off bores 18. The oil run-off bores 18 are oriented radially inward and in the direction of the regions 12 of the pin bosses 10, seen in the direction facing away from the piston crown, so that the oil flowing out of the cooling channel 5 hits the piston-crown-side regions 12 of the pin bosses 10, and thereby cools them.
As shown in the figures, the cooling channel 5 can be part of a cooled ring insert 4. However, it is also possible to dispose the cooling channel 5 at a distance from the ring insert, so that cooling of the combustion bowl 3 is thereby improved. Furthermore, it is sufficient, particularly in the case of smaller pistons, to cool only the pin boss 10, exclusively using a spray nozzle 19, by means of spray-on cooling, whereby the oil pockets 13, 14 for cooling and lubricating the pin boss 10 are filled with cooling oil.
REFERENCE SYMBOL LIST
- 1 piston
- 2 piston crown
- 3 combustion bowl
- 4 cooled ring insert
- 5 cooling channel
- 6 second groove
- 7 third groove
- 8 ring belt
- 9 piston skirt
- 10 pin boss
- 11 pin bore
- 12 piston-crown-side region of the pin boss 10
- 13, 14 oil pocket
- 15 zenith of the pin bore 11
- 16 oil spray nozzle
- 17 oil run-in bore
- 18 oil run-off bore
- 19 spray nozzle
- 20 oil
- 21 double spray nozzle
- 22 piston interior chamber
Claims
1. A piston for an internal combustion engine, comprising:
- a ring belt disposed on a radial outside of the piston, in the vicinity of a piston crown;
- a piston skirt that follows the ring belt in a direction facing away from the piston crown;
- a ring-shaped cooling channel disposed in a piston-crown-side edge region of the piston;
- at least one oil run-in bore and at least one oil run-off bore, which are each connected with an opening of the cooling channel and empty into an interior chamber of the piston;
- pin bosses held by the piston skirt, disposed on radially opposite sides, each having a pin bore, and
- at least one oil spray nozzle disposed in an interior chamber of the piston and directed at the at least one oil run-in bore, to introduce cooling oil into the cooling channel,
- wherein piston-crown-side regions of the pin bosses are reinforced radially inward, and wherein the oil run-off bores are directed at the reinforced regions of the pin bosses.
2. The piston according to claim 1, wherein oil pockets for short-term storage of oil are formed into the sides of the reinforced regions of the pin bosses that lie radially on the inside.
3. A piston for an internal combustion engine, comprising:
- a ring-shaped cooling channel disposed in a piston-crown-side edge region of the piston;
- at least one oil run-in bore and at least one oil run-off bore, which are each connected with an opening of the cooling channel and empty into an interior chamber of the piston;
- a piston skirt;
- pin bosses held by the piston skirt and disposed on radially opposite sides, each having a pin bore; and
- at least one oil spray nozzle disposed in an interior chamber of the piston and directed at the at least one oil run-in bore, to introduce cooling oil into the cooling channel,
- wherein for cooling of the pin bosses, the at least one oil spray nozzle is connected with an additional spray nozzle, directed at the pin bosses.
4. The piston according to claim 3, wherein piston-crown-side regions of the pin bosses are reinforced radially inward, and wherein the spray nozzles are each directed at a reinforced region of the pin bosses.
5. The piston according to claim 4, wherein oil pockets for short-term storage of oil are formed into the sides of the reinforced regions of the pin bosses that lie radially on an inside.
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- International Search Report.
Type: Grant
Filed: Dec 15, 2006
Date of Patent: Mar 8, 2011
Patent Publication Number: 20090007776
Assignee: Mahle International GmbH (Stuttgart)
Inventors: Arnold Benz (Aichwald), Helmut Kollotzek (Mutlangen), Markus Leitl (Remshalden), Sven Schilling (Korb), Ernst Limbach (Remshalden), Josip Zvonkovic (Weinstadt)
Primary Examiner: Michael Leslie
Attorney: Collard & Roe, P.C.
Application Number: 12/086,843
International Classification: F01B 31/08 (20060101);